JP2004233369A - Apparatus for detecting both acceleration and angular velocity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect two-axis components of acceleration and single-axis component of angular velocity, or single-axis component of acceleration and two-axis components of angular velocity with adequate response. <P>SOLUTION: The apparatus comprises excitation means 141 to 143 for exciting an oscillator 130, having a mass m in each axial direction and force-detecting means 151 to 153 for detecting force acting on the oscillator in each axial direction. The detected force in each axial direction is separated into a force f, resulting from acceleration and the Coriolis force F, which results from angular velocity by signal separation means 161 to 163. Based on each separated force f, acceleration calculation means 171 to 173 output each axial directional component of acceleration αx, αy, and αz. Based on each separated Coriolis force F, angular velocity calculation means 181 to 183 output each angular velocity about each axis ωx, ωy, and ωz. According to the acceleration components and angular velocity components required to be detected, necessary means are provided selectively. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an apparatus for detecting both acceleration and angular velocity, and more particularly to an apparatus for detecting acceleration and angular velocity based on a force acting on a vibrator.

  Conventionally, when detecting a physical quantity such as acceleration or angular velocity, it is common to use an acceleration detection device to detect acceleration and an angular velocity detection device to detect angular velocity. A device capable of detecting both of them has not been put to practical use at the commercial level at this stage to the knowledge of the present applicant. Conventionally, a one-dimensional acceleration detecting device for detecting a specific uniaxial acceleration and a one-dimensional angular velocity detecting device for detecting an angular velocity around a specific one axis are generally used, and two-dimensional or three-dimensional coordinate axes are generally used. In the case of detecting these physical quantities for each component, it is common to arrange an independent detection device for each coordinate axis.

However, in recent years, in the automobile industry, the machine industry, and the like, a demand for a detection device that can accurately detect a physical quantity such as acceleration or angular velocity has been increasing. In particular, there is a demand for a small detection device capable of detecting these physical quantities for each of the two-dimensional or three-dimensional coordinate axis components. In order to respond to such demands, the same inventor as the present application uses a single detection device to independently calculate acceleration in each coordinate axis direction in a three-dimensional coordinate system and angular velocity around an angular coordinate axis. Techniques for detecting have been proposed. That is, Patent Documents 1 and 2 below disclose novel detection devices that can detect acceleration and angular velocity for each coordinate axis component based on a force acting on a vibrator. The principle of detecting the angular velocity in this device utilizes Coriolis force. That is, when the vibrator is vibrated in the Y-axis direction while the angular velocity ωx about the X-axis is acting on the vibrator, the vibrator is excited using the principle that Coriolis force acts in the Z-axis direction. The means detects the Coriolis force acting in the Z-axis direction while vibrating in the Y-axis direction by means, and indirectly determines the angular velocity ωx about the X-axis based on the Coriolis force.
International Publication WO94 / 23272 JP-A-8-35981

  The above-described novel detection device is a relatively small device, but is capable of detecting six physical quantities, ie, accelerations in the X-axis, Y-axis, and Z-axis directions, and velocities around these axes. Device. However, in this device, it is necessary to detect the force acting on the vibrator both for detecting the acceleration and for detecting the angular velocity. That is, on the one hand, in a state where the vibrator is kept stationary, by detecting the force acting on the vibrator, the acceleration given from the outside is detected, and on the other hand, the vibrator is vibrated in a predetermined direction. In this state, the externally applied angular velocity is detected by detecting the Coriolis force acting on the vibrator. Therefore, when performing acceleration detection, the vibrator must be kept stationary, and when performing angular velocity detection, the vibrator must be kept in vibration.

  When such a detecting device is mounted on an automobile or an industrial machine and used, usually, it is required to detect an ever-changing acceleration and angular velocity in real time. In order to detect the acceleration and the angular velocity in real time using the above-described detection device, an operation of detecting the acceleration while keeping the vibrator stationary and an angular velocity detection while keeping the vibrator vibrated are required. The operation to be performed must be alternately and repeatedly performed. However, the mechanical responsiveness of the vibrator is limited, and it takes some time to vibrate the vibrator in a stationary state or to stop the vibrator in a vibrating state. For this reason, when an operation of detecting the acceleration and the angular velocity in real time is performed, a problem arises in that sufficient responsiveness cannot be obtained.

  Accordingly, the present invention provides a detection device capable of detecting both acceleration and angular velocity with sufficient responsiveness, and in particular, a device capable of simultaneously detecting a two-axis acceleration component and a one-axis angular velocity component, and a one-axis acceleration and an angular velocity two-axis component. It is an object of the present invention to provide a device that can simultaneously detect an axis component.

  The basic concept of the present invention is to provide a vibrator having a mass when detecting acceleration in a first axial direction and angular velocity around a second axis in a three-dimensional coordinate system, and a vibrator having the mass in the three-dimensional coordinate system. Exciting means for vibrating in the third axial direction at a sufficiently high frequency that can be identified with respect to the frequencies of the acceleration and angular velocity to be detected, and detecting the first axial force applied to the vibrator Force detection means, signal separation means for separating a bias component and an amplitude component from a detection signal obtained by the force detection means, acceleration calculation means for obtaining a first axial acceleration based on the bias component, The point is that both the acceleration and the angular velocity can be detected by providing the angular velocity calculating means for calculating the angular velocity around the second axis based on the amplitude component.

  In the detection device according to the present invention, a force acting on the vibrator is used for detecting both the acceleration and the angular velocity. According to the basic principle of the detection operation in this detection device, to detect the acceleration, it is sufficient to keep the vibrator in a stationary state and detect the force applied to the vibrator at that time, and to detect the angular velocity The vibrator may be kept in a vibrating state, and the force acting on the vibrator at that time may be detected. Based on such a basic principle, the inventor of the present application initially supposes that the acceleration detection in which the vibrator is in the stationary state and the angular velocity detection in which the vibrator is in the vibrating state are separately and independently performed. I was

  However, the present inventor has noticed that the acceleration detection and the angular velocity detection can be performed simultaneously. Now, for example, acceleration in a certain axial direction and angular velocity around a certain axis are acting simultaneously, and the acceleration and the angular velocity act on the vibrator vibrating in a predetermined direction in the same direction. Suppose that it was of a nature that caused In this case, the force acting on the vibrator is a combined force of a component caused by acceleration and a component caused by angular velocity. If the resultant force can be separated into a component caused by acceleration and a component caused by angular velocity, simultaneous detection of acceleration and angular velocity becomes possible.

  Such separation is possible when the vibration frequency of the vibrator is sufficiently high with respect to the frequencies of the acceleration and angular velocity to be detected. That is, under such conditions, the component caused by acceleration is synthesized as a bias component, and the component caused by angular velocity is synthesized as an amplitude component. Therefore, if the resultant force is separated into a bias component and an amplitude component, it is possible to independently obtain a component caused by the acceleration and a component caused by the angular velocity.

  In particular, the present invention provides the following devices for realizing a device that can simultaneously detect a two-axis acceleration component and a one-axis angular velocity component, and a device that can simultaneously detect a one-axis acceleration component and a two-axis angular velocity component. It can be implemented in embodiments.

(1) A first aspect of the present invention is to realize an apparatus for detecting acceleration in the Y-axis direction in an XYZ three-dimensional coordinate system, and angular velocities around the Y-axis and Z-axis.
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion connecting the vibrator and the fixed portion and having flexibility, the vibrator being fixed by bending of the flexible portion A structure configured to be displaced relative to the part;
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency of the acceleration and angular velocity to be detected;
First force detecting means for detecting a force applied to the vibrator in the Y-axis direction;
Second force detecting means for detecting a force in the Z-axis direction applied to the vibrator;
A first signal separating unit that separates a bias component and an amplitude component from a first detection signal obtained by the first force detecting unit;
A second signal separating unit that separates a bias component and an amplitude component from the second detection signal obtained by the second force detecting unit;
Acceleration calculation means for obtaining an acceleration in the Y-axis direction based on a bias component of the first detection signal;
A first angular velocity calculating means for driving the exciting means to vibrate the vibrator in the X-axis direction and for obtaining an angular velocity about the Y-axis based on an amplitude component of a second detection signal obtained in this state;
A second angular velocity calculating means for driving the excitation means to vibrate the vibrator in the X-axis direction, and for calculating an angular velocity about the Z-axis based on an amplitude component of the first detection signal obtained in this state;
Is provided.

(2) A second aspect of the present invention is to realize an apparatus for detecting acceleration in the X-axis direction in an XYZ three-dimensional coordinate system, and angular velocities around the Y-axis and Z-axis.
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion connecting the vibrator and the fixed portion and having flexibility, the vibrator being fixed by bending of the flexible portion A structure configured to be displaced relative to the part;
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency of the acceleration and angular velocity to be detected;
First force detecting means for detecting a force applied to the vibrator in the X-axis direction;
Second force detecting means for detecting a force applied to the vibrator in the Y-axis direction;
Third force detecting means for detecting a force in the Z-axis direction applied to the vibrator;
A first signal separating unit that separates a bias component and an amplitude component from a first detection signal obtained by the first force detecting unit;
A second signal separating unit that separates a bias component and an amplitude component from the second detection signal obtained by the second force detecting unit;
A third signal separating unit that separates a bias component and an amplitude component from a third detection signal obtained by the third force detecting unit;
Acceleration calculation means for obtaining an acceleration in the X-axis direction based on a bias component of the first detection signal;
A first angular velocity calculating means for driving the excitation means to vibrate the vibrator in the X-axis direction and for obtaining an angular velocity about the Y-axis based on an amplitude component of a third detection signal obtained in this state;
A second angular velocity calculating means for driving the exciting means to vibrate the vibrator in the X-axis direction, and for calculating an angular velocity about the Z-axis based on an amplitude component of a second detection signal obtained in this state;
Is provided.

(3) A third aspect of the present invention is to realize an apparatus for detecting acceleration in the Y-axis direction and acceleration in the Z-axis direction in an XYZ three-dimensional coordinate system, and an angular velocity around the Z-axis.
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion connecting the vibrator and the fixed portion and having flexibility, the vibrator being fixed by bending of the flexible portion A structure configured to be displaced relative to the part;
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency of the acceleration and angular velocity to be detected;
First force detecting means for detecting a force applied to the vibrator in the Y-axis direction;
Second force detecting means for detecting a force in the Z-axis direction applied to the vibrator;
A first signal separating unit that separates a bias component and an amplitude component from a first detection signal obtained by the first force detecting unit;
A second signal separating unit that separates a bias component and an amplitude component from the second detection signal obtained by the second force detecting unit;
First acceleration calculating means for obtaining an acceleration in the Y-axis direction based on a bias component of the first detection signal;
Second acceleration calculating means for obtaining acceleration in the Z-axis direction based on a bias component of the second detection signal;
An angular velocity calculating means for driving the exciting means to vibrate the vibrator in the X-axis direction and for obtaining an angular velocity about the Z-axis based on an amplitude component of the first detection signal obtained in this state;
Is provided.

(4) A fourth aspect of the present invention is to realize an apparatus for detecting acceleration in the Y-axis direction and acceleration in the Z-axis direction in an XYZ three-dimensional coordinate system, and an angular velocity around the Z-axis.
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion connecting the vibrator and the fixed portion and having flexibility, the vibrator being fixed by bending of the flexible portion A structure configured to be displaced relative to the part;
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency of the acceleration and angular velocity to be detected;
First force detecting means for detecting a force applied to the vibrator in the Y-axis direction;
Second force detecting means for detecting a force in the Z-axis direction applied to the vibrator;
Signal separating means for separating a bias component and an amplitude component from the first detection signal obtained by the first force detecting means;
First acceleration calculating means for obtaining an acceleration in the Y-axis direction based on a bias component of the first detection signal;
Second acceleration calculating means for obtaining acceleration in the Z-axis direction based on a second detection signal obtained by the second force detecting means;
An angular velocity calculating means for driving the exciting means to vibrate the vibrator in the X-axis direction and for obtaining an angular velocity about the Z-axis based on an amplitude component of the first detection signal obtained in this state;
Is provided.

(5) A fifth aspect of the present invention provides an apparatus for detecting acceleration in the X-axis direction and acceleration in the Y-axis direction in an XYZ three-dimensional coordinate system, and an angular velocity around the Z-axis.
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion connecting the vibrator and the fixed portion and having flexibility, the vibrator being fixed by bending of the flexible portion A structure configured to be displaced relative to the part;
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency of the acceleration and angular velocity to be detected;
First force detecting means for detecting a force applied to the vibrator in the X-axis direction;
Second force detecting means for detecting a force applied to the vibrator in the Y-axis direction;
A first signal separating unit that separates a bias component and an amplitude component from a first detection signal obtained by the first force detecting unit;
A second signal separating unit that separates a bias component and an amplitude component from the second detection signal obtained by the second force detecting unit;
First acceleration calculation means for obtaining an acceleration in the X-axis direction based on a bias component of the first detection signal;
Second acceleration calculating means for obtaining an acceleration in the Y-axis direction based on a bias component of the second detection signal;
An angular velocity calculating means for driving the exciting means to vibrate the vibrator in the X-axis direction and for obtaining an angular velocity about the Z-axis based on an amplitude component of the second detection signal obtained in this state;
Is provided.

  In carrying out the present invention described above, the signal separating means extracts each inflection point of the detection signal, and places the signal value of the two inflection points at an intermediate position on the time axis between two adjacent inflection points. A reference point having a signal value obtained by averaging is obtained, a signal obtained by connecting the obtained reference points is used as a bias component, and a signal corresponding to a difference between the detection signal and the bias component is used as an amplitude component. What should I do? The acceleration calculating means calculates the acceleration α based on the detected bias component f of the force and the mass m of the vibrator by applying an arithmetic expression of f = m · α. Is based on the detected amplitude component F of the force, the mass m of the vibrator, and the instantaneous speed v of the vibrator estimated from the operating state of the excitation means, and the calculation formula of F = 2m · v · ω is obtained. May be applied to obtain the angular velocity ω.

  As described above, according to the present invention, the combined force acting on the vibrating vibrator is separated into the force caused by the acceleration and the Coriolis force caused by the angular velocity, so that the acceleration and the angular velocity can be detected simultaneously, It is possible to realize a device that can simultaneously detect a two-axis acceleration component and a one-axis angular velocity component and a device that can simultaneously detect a one-axis acceleration component and a two-axis angular velocity component.

<<<< §1. Basic principle of angular velocity and acceleration detection >>>
First, the basic principle of angular velocity detection in the detection device according to the present invention will be described. The device according to the present invention can detect angular velocities around two axes or three axes. Here, the principle of uniaxial angular velocity detection will be briefly described first. FIG. 1 is a diagram showing the basic principle of the angular velocity detecting device disclosed on page 60 of the magazine "THE INVENTION", vol. 90, No. 3 (1993). Now, an XYZ three-dimensional coordinate system in which a prism-shaped vibrator 110 is prepared and X, Y, and Z axes are defined in directions as illustrated is considered. In such a system, it is known that the following phenomenon occurs when the vibrator 110 performs rotational movement at an angular velocity ω about the Z axis as a rotation axis. That is, when a vibration U that causes the vibrator 110 to reciprocate in the X-axis direction is applied, a Coriolis force F is generated in the Y-axis direction. In other words, when the vibrator 110 is rotated about the Z-axis while the vibrator 110 is vibrated along the X-axis in the figure, a Coriolis force F is generated in the Y-axis direction. This phenomenon is a mechanical phenomenon that has long been known as a Foucault pendulum, and the generated Coriolis force F is
F = 2m · v · ω
Is represented by Here, m is the mass of the vibrator 110, v is the instantaneous velocity of the vibration of the vibrator 110, and ω is the instantaneous angular velocity of the vibrator 110.

  The uniaxial angular velocity detecting device disclosed in the aforementioned magazine detects the angular velocity ω using this phenomenon. That is, as shown in FIG. 1, the first piezoelectric element 111 is provided on the first surface of the prismatic vibrator 110, and the second piezoelectric element 112 is provided on the second surface orthogonal to the first surface. Are respectively attached. As the piezoelectric elements 111 and 112, plate-like elements made of piezoelectric ceramics are used. The piezoelectric element 111 is used to apply the vibration U to the vibrator 110, and the piezoelectric element 112 is used to detect the generated Coriolis force F. That is, when an AC voltage is applied to the piezoelectric element 111, the piezoelectric element 111 repeatedly expands and contracts and vibrates in the X-axis direction. This vibration U is transmitted to the vibrator 110, and the vibrator 110 vibrates in the X-axis direction. As described above, when the vibrator 110 rotates at an angular velocity ω about the Z axis in a state where the vibration U is applied to the vibrator 110, Coriolis force F is generated in the Y-axis direction due to the above-described phenomenon. Since the Coriolis force F acts in the thickness direction of the piezoelectric element 112, a voltage V proportional to the Coriolis force F is generated on both surfaces of the piezoelectric element 112. Therefore, by measuring the voltage V, the angular velocity ω can be detected.

  The above-described conventional angular velocity detecting device is for detecting the angular velocity around the Z axis, and cannot detect the angular velocity around the X axis or the Y axis. In the detection device according to the present invention, as shown in FIG. 2, for a predetermined object 120, each of an angular velocity ωx about the X axis, an angular velocity ωy about the Y axis, and an angular velocity ωz about the Z axis in the XYZ three-dimensional coordinate system. Can be detected separately and independently. The basic principle will be described with reference to FIGS. Now, it is assumed that the transducer 130 is placed at the origin position of the XYZ three-dimensional coordinate system. In order to detect the angular velocity ωx of the vibrator 130 around the X axis, as shown in FIG. 3, when a vibration Uz in the Z axis direction is applied to the vibrator 130, a Coriolis force Fy generated in the Y axis direction is applied. Should be measured. The Coriolis force Fy has a value proportional to the angular velocity ωx. In order to detect the angular velocity ωy of the vibrator 130 about the Y-axis, as shown in FIG. 4, when the vibrator 130 is given a vibration Ux in the X-axis direction, a Coriolis generated in the Z-axis direction is generated. The force Fz may be measured. The Coriolis force Fz has a value proportional to the angular velocity ωy. Further, in order to detect the angular velocity ωz of the vibrator 130 about the Z-axis, as shown in FIG. 5, when the vibrator 130 is given a vibration Uy in the Y-axis direction, a Coriolis generated in the X-axis direction is generated. The force Fx may be measured. The Coriolis force Fx has a value proportional to the angular velocity ωz.

  As a result, in order to detect the angular velocity ωx about the X axis, the angular velocity ωy about the Y axis, and the angular velocity ωz about the Z axis in the XYZ three-dimensional coordinate system, as shown in FIG. The X-axis direction excitation unit 141 that provides the vibration Ux of the above, the Y-axis direction excitation unit 142 that provides the Y-axis direction vibration Uy, the Z-axis direction excitation unit 143 that provides the Z-axis direction vibration Uz, and the vibrator 130. X-axis direction force detection means 151 for detecting the acting X-axis direction Coriolis force Fx, Y-axis direction force detection means 152 for detecting the Y-axis direction Coriolis force Fy, Z-axis for detecting the Z-axis direction Coriolis force Fz What is necessary is just to prepare each of the direction force detection means 153.

  On the other hand, the principle of detecting acceleration is simpler. That is, when an acceleration α in a predetermined direction acts on a vibrator in a stationary state (functioning simply as a weight having a mass m), a force f of f = m · α acts in the same direction as the acceleration α. Will be. Therefore, if the axial forces fx, fy, fz acting on the vibrator 130 in the stationary state are detected, the accelerations αx, αy, αz in the respective axial directions can be detected by calculation using the mass m. .

  After all, in order to detect the acceleration αx in the X-axis direction, the acceleration αy in the Y-axis direction, and the acceleration αz in the Z-axis direction in the XYZ three-dimensional coordinate system, as shown in FIG. X-axis direction force detection means 151 for detecting an axial force fx, Y-axis direction force detection means 152 for detecting a Y-axis direction force fy, and a Z-axis direction force detection means 153 for detecting a Z-axis direction force fz. All you have to do is prepare them.

  FIG. 6 is a block diagram showing the components of the three-dimensional angular velocity detection device, and FIG. 7 is a block diagram showing the components of the three-dimensional acceleration detection device. Contains the latter configuration. That is, if excitation means 141, 142, and 143 for each axial direction are further added to the acceleration detection device shown in FIG. 7, the angular velocity detection device shown in FIG. 6 is obtained, and the angular velocity detection device shown in FIG. The device also functions as the acceleration detection device shown in FIG.

  However, since both angular velocity and acceleration are detected in the form of forces acting in the respective axial directions, if a single detector is used to detect both angular velocity and acceleration, the detected force will have an angular velocity component and Both the acceleration components will be included. As described above, the force caused by the angular velocity is a Coriolis force (having a magnitude of F = 2 m · v · ω) generated only when the vibrator is vibrated in a predetermined direction. In this specification, This will be indicated by a capital "F". In FIG. 6, Fx, Fy, and Fz, which are the detection targets of the force detection units 151, 152, and 153, are Coriolis forces generated due to angular velocities. On the other hand, the force resulting from the acceleration is a force (f = m · α) generated independently of the vibration of the vibrator, and is represented by a small letter “f” in this specification. In FIG. 7, fx, fy, and fz, which are the detection targets of the force detection units 151, 152, and 153, are all the forces generated due to the acceleration. In a state where both the angular velocity and the acceleration are acting on the vibrator 130, each of the force detecting means 151, 152, and 153 applies the Coriolis forces Fx, Fy, and Fz due to the angular velocity and the force fx due to the acceleration. , Fy, and fz are detected. The problem to be solved by the present invention is how to detect the Coriolis force F caused by the angular velocity and the force f caused by the acceleration separately in such a situation.

<<<< §2. Specific detection device structure suitable for implementing the present invention >>>>>
The basic configuration of the detection device according to the present invention is as shown in the block diagram of FIG. 6, and the present invention is applicable to any detection device having such a configuration. It is. Regarding the specific structure of the detection device having the configuration shown in the block diagram of FIG. 6, various embodiments are disclosed in Patent Documents 1 and 2 mentioned above. The present invention does not relate to the specific structure of such a detection device, but to signal processing of a detection signal obtained from such a detection device. Therefore, here, only an example of a specific structure of such a detection device will be described for reference. Of course, the technical scope of the present invention is not at all limited by the specific structures described herein.

  FIG. 8 is a perspective view of this specific detection device as viewed obliquely from above, and FIG. 9 is a perspective view of this detection device as viewed obliquely from below. In this detection device, twelve upper electrodes A1 to A8 and E1 to E4 are formed on the upper surface of a disc-shaped piezoelectric element 10, and one lower electrode B is formed on the lower surface. Here, for convenience of explanation, the origin O of the XYZ three-dimensional coordinate system is defined at the center position of the upper surface of the disc-shaped piezoelectric element 10, and the X axis and the Y axis are defined in directions along the upper surface of the piezoelectric element 10. , Z-axis is defined as a direction going upward and perpendicular to the upper surface. Therefore, the upper surface of the piezoelectric element 10 is included in the XY plane.

  A structural feature of the piezoelectric element 10 is that an annular groove 15 is formed on the lower surface as shown in FIG. In this embodiment, the annular groove 15 has a circular shape surrounding the origin O. The lower electrode B is a single electrode layer, and is formed on the entire lower surface of the piezoelectric element 10 including the inside of the annular groove 15. On the other hand, the twelve upper electrodes A1 to A8 and E1 to E4 all have a band shape along an arc centered on the origin O, as clearly shown in the top view of FIG. The shape is line-symmetric with respect to the axis or the Y axis.

  The structure of this detection device becomes more apparent with reference to FIG. FIG. 11 is a side sectional view of the detection device taken along the XZ plane. The portion of the piezoelectric element 10 where the annular groove 15 is formed is thinner than other portions and has flexibility. Here, a portion of the piezoelectric element 10 located above the annular groove 15 is called a flexible portion 12, a central portion surrounded by the flexible portion 12 is called a central portion 11, The portion located on the outer periphery is referred to as a peripheral portion 13. The relative positional relationship of these three parts is clearly shown in the bottom view of FIG. That is, the flexible portion 12 is formed in the portion around the center portion 11 where the annular groove 15 is formed, and the peripheral portion 13 is formed around the flexible portion 12.

  Here, for example, when only the surrounding portion 13 is fixed to the detecting device housing and the entire detecting device housing is shaken, a force based on the acceleration acts on the central portion 11 due to its mass, and the flexible portion 12 Will bend. In other words, the central portion 11 is supported from the periphery by the flexible portion 12 having flexibility, and can generate a certain amount of displacement in the X-axis, Y-axis, and Z-axis directions. Eventually, the central portion 11 in this detection device functions as the vibrator 130 having mass in the detection device shown in FIG. In the detection device shown in FIG. 6, in addition to the vibrator 130, excitation means 141, 142, 143 in each axial direction and force detection means 151, 152, 153 in each axial direction are required. In this specific detection device, the excitation means 141, 142, and 143 are constituted by the upper electrodes E1 to E4, the lower electrode B, and the piezoelectric element 10 interposed therebetween, and the force detection means 151 , 152, 153 are composed of upper electrodes A1 to A8, lower electrode B, and piezoelectric element 10 sandwiched between them.

  In order to explain that the excitation means and the force detection means can be constituted by the upper and lower electrodes and the piezoelectric element 10 sandwiched therebetween, first, basic properties of the piezoelectric element 10 will be confirmed. . In general, a piezoelectric element causes a polarization phenomenon by the action of mechanical stress. That is, when a stress is applied in a specific direction, a positive charge is generated on one side and a negative charge is generated on the other side. In the detection device of this embodiment, a piezoelectric ceramic having polarization characteristics as shown in FIG. That is, as shown in FIG. 13A, when a force extending in the direction extending along the XY plane acts, a positive charge is generated on the upper electrode A side, and a negative charge is generated on the lower electrode B side. Conversely, as shown in FIG. 13B, when a force in the direction of contraction along the XY plane acts, a negative charge is applied to the upper electrode A and a positive charge is applied to the lower electrode B. , Have polarization characteristics as they occur. Conversely, when a predetermined voltage is applied to the upper and lower electrodes, a mechanical stress acts on the inside of the piezoelectric element 10. That is, as shown in FIG. 13A, when a voltage is applied so as to give a positive charge to the upper electrode A side and a negative charge to the lower electrode B side, a force in the direction extending along the XY plane is applied. When a voltage is applied so as to give a negative charge to the upper electrode A side and a positive charge to the lower electrode B side, as shown in FIG. 13 (b), the direction of contraction along the XY plane is reduced. The force is generated.

  The specific detection device described here configures each excitation unit and each force detection unit by utilizing such a property of the piezoelectric element. In other words, each excitation means is configured by utilizing the property that stress can be generated inside the piezoelectric element by applying a voltage to the upper and lower electrodes, and when the stress acts on the inside of the piezoelectric element, electric charges are applied to the upper and lower electrodes. Each force detecting means is configured by utilizing the property of generating the force. Hereinafter, the configuration and operation of each of these units will be described.

<X-axis direction excitation means>
Among the components shown in FIG. 6, the X-axis direction excitation means 141 includes upper electrodes E1 and E2, a part of the lower electrode B opposed thereto, a part of the piezoelectric element 10 sandwiched between the upper electrodes E1 and E2, Supply means. Now, consider a case where a positive voltage is applied to the upper electrode E1 and a negative voltage is applied to the upper electrode E2 while keeping the lower electrode B at the reference potential. Then, as shown in the side sectional view of FIG. 14, a stress is generated in the piezoelectric element below the electrode E1 in the direction extending left and right in the figure, and the piezoelectric element below the electrode E2 is stressed in the direction contracting left and right in the figure. (See the polarization characteristics in FIG. 13). Therefore, the piezoelectric element 10 as a whole is deformed as shown in FIG. 14, and the center of gravity P of the center portion 11 is displaced by Dx in the X-axis direction. Here, when the polarity of the voltage applied to the upper electrodes E1 and E2 is reversed, a negative voltage is applied to the upper electrode E1, and a positive voltage is applied to the upper electrode E2, contrary to FIG. In the piezoelectric element, stress in the direction of contracting left and right in the drawing occurs, and in the piezoelectric element below the electrode E2, stress in the direction extending in the left and right directions of the drawing occurs. Will be displaced in the direction by -Dx.

  Therefore, a first AC voltage is applied between the lower electrode B and the upper electrode E1, and a second AC voltage is applied between the lower electrode B and the upper electrode E2 such that the first AC voltage has an opposite phase to the first AC voltage. 2, the center of gravity P alternately generates a displacement of Dx and a displacement of -Dx along the X-axis direction, and the center portion 11 vibrates along the X-axis. Will do. As described above, the center portion 11 corresponds to the vibrator 130 in the components shown in FIG. Therefore, it becomes possible to apply the vibration Ux in the X-axis direction to the vibrator 130 by applying the AC voltage described above. The frequency of the vibration Ux can be controlled by the frequency of the applied AC voltage, and the amplitude of the vibration Ux can be controlled by the amplitude value of the applied AC voltage. After all, the upper electrodes E1 and E2, the lower electrode B, the piezoelectric element 10, and the means for supplying an AC voltage (not shown) constitute the X-axis direction excitation means 141 shown in FIG.

<Y-axis direction excitation means>
Among the components shown in FIG. 6, the Y-axis direction excitation means 142 is illustrated with the upper electrodes E3 and E4, a part of the lower electrode B opposed thereto, and a part of the piezoelectric element 10 sandwiched therebetween. And no AC supply means. The operation principle is exactly the same as the operation principle of the X-axis direction excitation means 141 described above. That is, as shown in the top view of FIG. 10, the upper electrodes E1 and E2 are arranged on the X axis, whereas the upper electrodes E3 and E4 are arranged on the Y axis. Therefore, by supplying AC voltages having phases inverted to each other to the upper electrodes E1 and E2, the upper electrodes E3 and E4 are vibrated in the X-axis direction according to the same principle as that of the upper electrodes E3 and E4. By supplying AC voltages having phases inverted to each other, the central portion 11 (vibrator) can be vibrated in the Y-axis direction.

  That is, by applying the above-described AC voltage, it becomes possible to apply a vibration Uy in the Y-axis direction to the vibrator 130. The frequency of the vibration Uy can be controlled by the frequency of the applied AC voltage, and the amplitude of the vibration Uy can be controlled by the amplitude value of the applied AC voltage. As a result, the upper electrodes E3 and E4, the lower electrode B, the piezoelectric element 10, and a means for supplying an AC voltage (not shown) constitute the Y-axis direction exciting means 142 shown in FIG.

<Z-axis direction excitation means>
Among the components shown in FIG. 6, the Z-axis direction excitation means 143 includes upper electrodes E1 to E4, a part of the lower electrode B opposed thereto, a part of the piezoelectric element 10 sandwiched between the upper electrodes E1 to E4, Supply means. Now, consider a case where a negative voltage is applied to the upper electrodes E1 and E2 and a positive voltage is applied to the upper electrodes E3 and E4 while the lower electrode B is maintained at the reference potential. Then, as shown in the side sectional view of FIG. 15, a stress is generated in the piezoelectric element below the electrodes E1 and E2 in the direction of contraction in the left-right direction (and the direction perpendicular to the paper surface) of FIG. A stress is generated in the piezoelectric element in a direction extending in a direction perpendicular to the plane of the drawing (and in the horizontal direction in the drawing) (see the polarization characteristics in FIG. 13). Here, as is clear from the top view of FIG. 10, the upper electrodes E1 and E2 are located outside the flexible portion 12, and the upper electrodes E3 and E4 are located inside the flexible portion 12. For this reason, when each of the above-mentioned stresses is generated, the piezoelectric element 10 as a whole is deformed as shown in FIG. 15, and the center of gravity P of the center portion 11 is displaced by Dz in the Z-axis direction. Become. Here, when the polarity of the voltage applied to the upper electrodes E1 to E4 is reversed, a positive voltage is applied to the upper electrodes E1 and E2, and a negative voltage is applied to the upper electrodes E3 and E4, the opposite of FIG. The piezoelectric element below E1 and E2 generates a stress in the extending direction, and the piezoelectric element below the electrodes E3 and E4 generates a stress in the contracting direction. As a result, the center of gravity P of the center portion 11 is Will be displaced in the direction by -Dz.

  Therefore, a first AC voltage is applied between the lower electrode B and the upper electrodes E1 and E2, and a phase opposite to the first AC voltage is applied between the lower electrode B and the upper electrodes E3 and E4. By applying such a second AC voltage, the center of gravity P alternately generates a displacement of Dz and a displacement of -Dz along the Z-axis direction, and the center portion 11 is moved along the Z-axis. Will vibrate along. As described above, the center portion 11 corresponds to the vibrator 130 in the components shown in FIG. Therefore, by applying the above-described AC voltage, it becomes possible to apply vibration Uz in the Z-axis direction to the vibrator 130. The frequency of the vibration Uz can be controlled by the frequency of the applied AC voltage, and the amplitude of the vibration Uz can be controlled by the amplitude value of the applied AC voltage. As a result, the Z-axis direction excitation means 143 shown in FIG. 6 is constituted by the upper electrodes E1 to E4, the lower electrode B, the piezoelectric element 10, and a means for supplying an AC voltage (not shown).

<X-axis direction force detection means>
Among the components shown in FIG. 6, the X-axis direction force detecting means 151 includes upper electrodes A1 and A2, a part of the lower electrode B opposed thereto, and a part of the piezoelectric element 10 sandwiched therebetween, which will be described later. And a detection circuit. Now, a description will be given of what phenomenon occurs when a force fx based on acceleration acts on the center of gravity P of the center portion 11 (vibrator 130) in a state where the peripheral portion 13 of the detection device is fixed to the housing. I do. First, let us consider a case where a force fx in the X-axis direction acts on the center of gravity P as shown in FIG. 16 as a result of the acceleration αx in the X-axis direction being applied to the center of gravity P. By the action of such a force fx, the flexible portion 12 is bent, and the deformation as shown in FIG. 16 occurs. As a result, the upper electrodes A1 and A6 arranged along the X axis extend in the X axis direction, and the upper electrodes A5 and A2 similarly arranged along the X axis contract in the X axis direction. Since the piezoelectric elements located below these upper electrodes have polarization characteristics as shown in FIG. 13, charges of the polarity shown in FIG. 16 are generated in each upper electrode. At this time, since the lower electrode B is a single common electrode, even if charges having a polarity of "+" or "-" are partially generated, the charges are canceled and no charge is generated in total.

  Therefore, if the difference between the charge generated on the upper electrode A1 and the charge generated on the upper electrode A2 is obtained, the force fx acting in the X-axis direction can be obtained. Of course, the force fx acting in the X-axis direction can also be obtained from the difference between the charge generated on the upper electrode A5 and the charge generated on the upper electrode A6. However, as will be described later, the upper electrodes A5 and A6 Since it is used for detecting the force fx acting in the axial direction, it is not used for detecting the force fx in the X-axis direction. In the above description, the case where the force fx acting due to the acceleration is detected is taken as an example. However, the Coriolis force Fx acting due to the angular velocity can be detected in exactly the same manner. Actually, as the force acting on the center of gravity P in the X-axis direction, the force fx caused by the acceleration and the Coriolis force Fx caused by the angular velocity are equivalent, and cannot be distinguished as the force detected instantaneously.

<Y-axis direction force detection means>
Among the components shown in FIG. 6, the Y-axis direction force detecting means 152 includes upper electrodes A3 and A4, a part of the lower electrode B opposed thereto, a part of the piezoelectric element 10 sandwiched between these, and will be described later. And a detection circuit. The detection principle is the same as the detection principle of the X-axis direction force detection means 151 described above. That is, when the force fy based on the acceleration acts on the center of gravity P of the center portion 11 (vibrator 130) in a state where the peripheral portion 13 of the detection device is fixed to the housing, what kind of phenomenon occurs can be considered. Just fine. When a force fy in the Y-axis direction acts as a result of the acceleration αy in the Y-axis direction applied to the center of gravity P, a negative charge is generated in the upper electrode A3 and a positive charge is generated in the upper electrode A4. Therefore, if the difference between the charge generated in the upper electrode A3 and the charge generated in the upper electrode A4 is obtained, the force fy acting in the Y-axis direction can be obtained. The detection of the Coriolis force Fy acting due to the angular velocity is exactly the same.

<Z-axis direction force detection means>
6, the Z-axis direction force detecting means 153 includes upper electrodes A5 to A8, a part of the lower electrode B opposed thereto, a part of the piezoelectric element 10 sandwiched between the upper electrodes A5 to A8, which will be described later. And a detection circuit. Now, a description will be given of what phenomenon occurs when a force fz based on the acceleration acts on the center of gravity P of the center portion 11 (vibrator 130) in a state where the peripheral portion 13 of the detection device is fixed to the housing. I do. First, let us consider a case where, as a result of applying the acceleration αz in the Z-axis direction to the center of gravity P, a force fz in the Z-axis direction acts on the center of gravity P as shown in FIG. By the action of such a force fz, the flexible portion 12 is bent, and a deformation as shown in FIG. 17 occurs. As a result, since the upper electrodes A1, A8, A2, and A7 arranged in the outer annular region shrink, charges of "-" are generated on the upper electrode side, and the upper electrodes A5, A4, and A6 arranged in the inner annular region. , A3 are extended, so that "+" charges are generated on the upper electrode side. At this time, since the lower electrode B is a single common electrode, even if charges having a polarity of "+" or "-" are partially generated, the charges are canceled and no charge is generated in total.

  Therefore, if the difference between the sum of the charges generated in the upper electrodes A5 and A6 and the sum of the charges generated in the upper electrodes A7 and A8 is obtained, the force fz acting in the Z-axis direction can be obtained. Of course, the Coriolis force Fz acting due to the angular velocity can be detected in exactly the same manner.

  Here, a table shown in FIG. 18 is obtained by summarizing the polarities of the charges generated in each upper electrode when each of the forces fx, fy and fz acts. In the table, "0" indicates that the piezoelectric element partially expands but partially contracts, so that positive and negative are canceled out and no charge is generated as a whole. As described above, since each upper electrode has a shape that is line-symmetric with respect to the X axis or the Y axis, electric charges are generated even when the force fy acts on the upper electrodes that generate electric charges by the action of the force fx. Conversely, no charge is generated on the upper electrode that generates charge by the action of the force fy even if the force fx acts. As described above, it is important to keep the electrode shape line-symmetric in order to avoid other-axis interference. The table in FIG. 18 shows the polarities when the positive force + fx, + fy, + fz of each axis acts, but the negative force -fx, -fy, -fz of each axis. Will cause charges of opposite polarity to appear in this table. The fact that such a table is obtained can be easily understood by referring to the deformed state shown in FIGS. 16 and 17 and the arrangement of each upper electrode shown in FIG. Also, the magnitude of the applied force can be detected as the amount of generated charge.

  In order to detect the forces fx, fy, fz (or Coriolis forces Fx, Fy, Fz) based on such a principle, for example, a detection circuit as shown in FIG. 19 may be prepared. In this detection circuit, the Q / V conversion circuits 31 to 38 are circuits that convert the amount of charge generated in each of the upper electrodes A1 to A8 into a voltage value when the potential of the lower electrode B is used as a reference potential. For example, when a “+” charge is generated in the upper electrode from this circuit, a positive voltage (relative to the reference potential) corresponding to the generated charge is output, and conversely, “ When a charge of "-" is generated, a negative voltage (relative to the reference potential) corresponding to the generated charge amount is output. The voltages V1 to V8 output in this manner are supplied to arithmetic units 41 to 43, and outputs of these arithmetic units 41 to 43 are obtained at terminals Tx, Ty, and Tz. Here, the voltage value of the terminal Tx with respect to the reference potential becomes the detection value of the force fx (or Coriolis force Fx), the voltage value of the terminal Ty with respect to the reference potential becomes the detection value of the force fy (or Coriolis force Fy), The voltage value with respect to the reference potential is the detected value of the force fz (or Coriolis force Fz).

  It can be seen by referring to the table of FIG. 18 that the voltage values obtained at the respective output terminals Tx, Ty, Tz become the detection values of the forces fx, fy, fz. For example, when the force fx acts, a charge of “+” is generated on the upper electrode A1, and a charge of “−” is generated on the upper electrode A2. Therefore, V1 is positive and V2 is negative. Therefore, the arithmetic unit 41 performs an operation of V1−V2 to obtain the sum of the absolute values of the voltages V1 and V2, and outputs the sum to the terminal Tx as a detected value of the force fx. Similarly, when the force fy acts, a charge of “−” is generated on the upper electrode A3, and a charge of “+” is generated on the upper electrode A4. Therefore, V3 is negative and V4 is positive. Therefore, the arithmetic unit 42 performs an operation of V4−V3 to obtain the sum of the absolute values of the voltages V3 and V4, and this is output to the terminal Ty as a detected value of the force fy. When the force fz is applied, a “+” charge is generated on the upper electrodes A5 and A6, and a “−” charge is generated on the upper electrodes A7 and A8. Therefore, V5 and V6 are positive and V7 and V8 are negative. Then, the arithmetic unit 43 performs an operation of V5 + V6-V7-V8 to obtain the sum of the absolute values of the voltages V5 to V8, and outputs the sum to the terminal Tz as a detected value of the force fz.

  It should be noted here that the detection values obtained at the output terminals Tx, Ty, Tz do not include other axis components. For example, as shown in the table of FIG. 18, when only the force fx acts, no charge is generated in the upper electrodes A3 and A4 for detecting the force fy, and no detection voltage is obtained at the terminal Ty. . At this time, although electric charges (polarities opposite to each other) are generated in the upper electrodes A5 and A6 for detecting the force fz, the voltages V5 and V6 are added to each other in the arithmetic unit 43 and thus cancel each other. Does not provide a detection voltage. Similarly, when only the force fy acts, no detection voltage can be obtained other than at the terminal Ty. Similarly, when only the force fz is applied, no detection voltage is obtained except at the terminal Tz. In this way, the X, Y, and Z axial components can be detected independently.

  Although one specific configuration example of the detection device illustrated in FIG. 6 has been described above, various other configuration examples are possible. In short, what kind of configuration would be possible if excitation means for mechanically vibrating the vibrator 130 in a predetermined axial direction and detecting means capable of detecting forces in each axial direction acting on the vibrator 130 could be realized. You can take it.

<<<< §3. Conventionally proposed detection operation >>>
The conventional detection operation for detecting the accelerations αx, αy, αz in the respective axial directions and the angular velocities ωx, ωy, ωz around the angular axes by the detection device as shown in FIG. The operation is shown in the flowchart of FIG. This detection operation is a method disclosed in Patent Document 1 mentioned above.

  First, in step S11, detection values of the force detection units 151, 152, and 153 are obtained in a state where vibration is not applied to the vibrator 130 (that is, a state in which the excitation units 141, 142, and 143 are not driven). In this case, the detection device shown in FIG. 6 is operated as the acceleration detection device shown in FIG. 7, and the detection values of the respective force detection means 151, 152, and 153 indicate the forces fx, fy, and fx caused by the acceleration. It becomes. Since the vibrator 130 does not vibrate, Coriolis forces Fx, Fy, and Fz resulting from the angular velocity are not detected. Since there is a relationship of f = m · α between the force f due to the acceleration and the acceleration α based on the mass m of the vibrator 130, each axis is obtained based on the obtained forces fx, fy and fz. The accelerations αx, αy, αz in the directions can be detected.

  Subsequently, in step S12, the detection value Fy of the Y-axis direction force detection unit 152 is obtained in a state where the vibration Uz is applied to the vibrator 130 (that is, the state where the Z-axis direction excitation unit 143 is driven). Then, the angular velocity ωx around the X axis is detected based on the equation of Fy = 2m · vz · ωx. Here, m is the mass of the vibrator 130, and vz is the instantaneous velocity of the vibrator 130 in the Z-axis direction. This detection method is based on the principle shown in FIG. Note that the instantaneous speed vz can be estimated from the operation state of the Z-axis direction excitation unit 143. For example, in the specific configuration example shown in §2 described above, the Z-axis direction excitation means 143 is driven by supplying a predetermined AC voltage to the upper electrodes E1 to E4. , Frequency, and the phase at the instantaneous instant, the instantaneous velocity vz can be estimated.

  In the next step S13, the detection value Fz of the Z-axis direction force detection unit 153 is obtained in a state where the vibration Ux is applied to the vibrator 130 (that is, the state where the X-axis direction excitation unit 141 is driven). Then, the angular velocity ωy about the Y axis is detected based on the equation of Fz = 2m · vx · ωy. Here, vx is the instantaneous velocity of the vibrator 130 in the X-axis direction, and can be estimated from the operation state of the X-axis direction excitation means 141. This detection method is based on the principle shown in FIG.

  Subsequently, in step S14, the detection value Fx of the X-axis direction force detection unit 151 is obtained in a state where the vibration Uy is applied to the vibrator 130 (that is, the state where the Y-axis direction excitation unit 142 is driven). Then, the angular velocity ωz about the Z axis is detected based on the equation of Fx = 2m · vy · ωz. Here, vy is the instantaneous velocity of the vibrator 130 in the Y-axis direction, and can be estimated from the operation state of the Y-axis direction excitation means 142. This detection method is based on the principle shown in FIG.

  Finally, as long as the detection operation is continued after step S15, the processing from step S11 is repeatedly executed. Thus, the step of detecting the accelerations αx, αy, αz in the respective axial directions without vibrating the vibrator 130 (step S11), and the respective speeds around the respective axes with the vibrator 130 vibrating in the predetermined direction. By separately performing the steps of detecting ωx, ωy, and ωz (steps S12 to S14), both the acceleration and the angular velocity are obtained. In an environment where acceleration and angular velocity are constantly acting, forces fx, fy, and fz due to acceleration are mixed with Coriolis forces Fx, Fy, and Fz in the angular velocity detection process in steps S12 to S14. Therefore, it is necessary to perform subtraction using the values of fx, fy, and fz detected in step S11 to extract only the components of the Coriolis forces Fx, Fy, and Fz.

  The problem of the "basic detection operation" is that the response becomes poor when used for the purpose of continuously measuring the values of acceleration and angular velocity. 2. Description of the Related Art In automobiles and industrial machines, it is often required to continuously obtain values of acceleration and angular velocity that change every moment in a constant time cycle. However, when performing the detection operation based on the flowchart shown in FIG. 20, the vibrator that has been stationary in step S11 is vibrated in the Z-axis direction in step S12, vibrated in the X-axis direction in step S13, and Y-vibrated in step S14. It is necessary to vibrate in the axial direction and stop again in step S11. It is very difficult to change such mechanical vibration conditions for the vibrator at high speed, and in reality, in order to proceed to the next step in the detection operation of FIG. It takes some time to get For this reason, the responsiveness must be deteriorated.

<<<< §4. Separation of force due to acceleration and force due to angular velocity >>>>>
The feature of the detection operation according to the present invention resides in that the detection of the acceleration and the detection of the angular velocity are simultaneously performed. For this purpose, it is necessary to separate the forces detected by the force detecting means 151, 152, and 153 into a force caused by acceleration and a Coriolis force caused by angular velocity. Here, this separation method will be described with reference to a specific example.

  Here, a specific example using the model shown in FIG. 3 as an example will be described. FIG. 3 is a diagram illustrating the principle of detecting the angular velocity ωx about the X axis. That is, when the Coriolis force Fy generated in the Y-axis direction is detected in a state where the vibration Uz in the Z-axis direction is applied to the vibrator 130, the angular velocity around the X-axis is obtained from the relational expression of Fy = 2m · vz · ωx. ωx is obtained. Now, let us consider a case where an angular velocity ωx about the X axis acts as shown in FIG. 21B in a state where a vibration Uz in the Z-axis direction as shown in FIG. . In each case, the horizontal axis is time t. The vibration Uz indicates a change in the physical position of the vibrator 130. In this example, the vibration Uz is performing a sine motion up and down. Further, the angular velocity ωx acting in this case is an angular velocity around the positive direction of the X-axis (for example, clockwise), and gradually increases with time and gradually decreases. At this time, the Coriolis force Fy generated in the Y-axis direction is obtained by a relational expression of Fy = 2m · vz · ωx. Here, the instantaneous velocity vz of the vibrator 130 in the Z-axis direction is obtained by setting the phase of the vibration Uz to (π / 2). This is because the instantaneous velocity of an object that is sine-moving up and down becomes maximum at the moment when the object passes through the center position, and becomes 0 at the uppermost point and the lowermost point (here, FIG. 21 (a) In the vibration shown in (1), the speed in the downward direction is defined as positive, and the speed in the upward direction is defined as negative). Since the mass m of the vibrator 130 is constant, the Coriolis force Fy is determined by the product of the instantaneous velocity vz and the angular velocity ωx, and is as shown in FIG. After all, in the model shown in FIG. 3, when the oscillator 130 is given a vibration Uz as shown in FIG. 21 (a) and an angular velocity ωx as shown in FIG. A Coriolis force Fy as shown in FIG.

  On the other hand, when acceleration in the Y-axis direction acts on the vibrator 130, what kind of force is generated in the Y-axis direction? Since the force fy in the Y-axis direction caused by the acceleration αy in the Y-axis direction is given by the relational expression fy = m · αy, a force fy proportional to the given acceleration αy is generated. Therefore, if an acceleration αy that linearly increases is given to the vibrator 130, a force fy in the Y-axis direction as shown in FIG. 21D is generated.

  Then, in the model of FIG. 3, in a state where the vibration Uz in the Z-axis direction as shown in FIG. 21A is given to the vibrator 130, the angular velocity ωx around the X-axis as shown in FIG. When a linearly increasing acceleration αy in the Y-axis direction acts and acts, what kind of force is observed in the Y-axis direction? In this case, naturally, a resultant force corresponding to the sum of the Coriolis force Fy as shown in FIG. 21C and the force fy based on the acceleration as shown in FIG. 21D is observed. FIG. 22 shows such a combined force fy + Fy.

  If the resultant force fy + Fy can be separated into the force fy and the Coriolis force Fy, the acceleration αy in the Y-axis direction can be obtained from the former, and the angular velocity ωx about the X-axis can be obtained from the latter. be able to. That is, simultaneous detection of acceleration and angular velocity becomes possible. The present inventor has found that this separation can be performed by focusing on the following points. That is, if only the bias component is extracted from the composite force fy + Fy shown in FIG. 22, only the force fy shown in FIG. 21D can be extracted, and if only the amplitude component is extracted, FIG. Only the Coriolis force Fy shown can be taken out. First, the Coriolis force Fy shown in FIG. 21 (c) is obtained by amplitude-modulating the angular velocity ωx shown in FIG. 21 (b) using the vibration Uz shown in FIG. 21 (a) as a carrier. Therefore, the information on the angular velocity ωx is included only as an amplitude component in the resultant force. On the other hand, since the force fy shown in FIG. 21D does not include the frequency component of the vibration Uz, the information is included only as a mere bias component in the resultant force. Focusing on such a point, it can be understood that, of the combined force fy + Fy, the force fy can be extracted by extracting only the bias component, and the Coriolis force Fy can be extracted by extracting only the amplitude component.

  In order to separate the force f based on the acceleration and the Coriolis force F based on the angular velocity based on such a principle, the frequency of the vibration U must be distinguished from the frequency of the acceleration or the angular velocity to be detected. It must be of a sufficiently high frequency. In other words, in the detection device according to the present invention, only the frequency components sufficiently lower than the frequency of the vibration U can be detected from the acceleration and the angular velocity to be detected. However, such a restriction poses no practical problem at all as a detection device mounted on an automobile or an industrial machine. Specifically, when a vibrator using a piezoelectric element as described in §2 is vibrated, it is most efficient to vibrate at a resonance frequency of about 20 kHz. In this case, it is sufficiently possible to detect an acceleration or an angular velocity having a frequency component of several hundred Hz or less, and such performance is required for a detection device mounted on a general automobile or an industrial machine. Is fully satisfied.

  Now, as a method of separating the combined force into a bias component and an amplitude component based on the above-described principle, for example, a method using a frequency filter can be used. However, in recent years, with the spread of computers, it has become common to perform A / D conversion on the obtained electric signals and perform digital processing. The inventor of the present application has found the following separation method using such digital processing.

  First, as shown in FIG. 23, the inflection points P1 to P9 are extracted from the detection signal of the combined force fy + Fy as shown in FIG. Then, as shown in FIG. 24, the division lines Q1 to Q9 indicating the positions of the inflection points P1 to P9 on the time axis t are defined, and the reference lines Q12 to Q89 (FIG. 24 is indicated by a broken line). Then, on each reference line, a reference point m having the average value of the signal values of the inflection points on both sides thereof is plotted. FIG. 25 shows the reference points m1 to m8 thus plotted. For example, the reference point m1 is a point on the reference line Q12 having the average value of the signal value of the inflection point P1 and the signal value of the inflection point P2. When the reference points m1 to m8 are obtained in this way, as shown in FIG. 26, a signal waveform connecting these in order is obtained. The signal waveform thus obtained corresponds to the bias component of the original composite force fy + Fy, and eventually corresponds to the force fy based on the acceleration αy. When the bias component is obtained, a signal waveform corresponding to the amplitude component can be obtained by subtracting the bias component from the original combined force, and eventually, a signal waveform corresponding to the Coriolis force Fy can be obtained. The magnitude of the angular velocity ωx can be obtained by extracting an envelope E of a signal waveform corresponding to the Coriolis force Fy, as shown in FIG. The direction of the angular velocity ωx can be obtained from the phase difference between the obtained Coriolis force Fy and the vibration Uz shown in FIG. For example, when the angular velocity ωx in the positive direction shown in FIG. 21B is applied, the waveform of the Coriolis force Fy obtained in FIG. 21A is different from the waveform of the vibration Uz shown in FIG. As shown in (c), the phase is shifted to the right by (π / 2), but when a negative angular velocity -ωx is applied, the vibration shown in FIG. With respect to the Uz waveform, a Coriolis force waveform in which the sign of FIG. 21 (c) is inverted is obtained. In the Coriolis force waveform, the phase of the vibration Uz waveform is shifted to the left by (π / 2). Become something.

<<<< §5. First Embodiment of Detection Device According to the Present Invention >>
The detection device according to the present invention, based on the basic principle described in §4 above, separates a combined force into a force f (bias component) based on acceleration and a Coriolis force F (amplitude component) based on angular velocity. In this method, the acceleration and the angular velocity can be detected at the same time by using means. FIG. 28 is a block diagram showing a basic configuration of the detection device according to the first example of the present invention. This detection device adds an X-axis direction signal separation unit 161, a Y-axis direction signal separation unit 162, and a Z-axis direction signal separation unit 163 to each component of the detection device shown in FIG. 171 to 173 and angular velocity calculating means 181 to 183 are added.

  Each of the signal separating means 161 to 163 converts the combined force fx + Fx, fy + Fy, fz + Fz obtained from each of the force detecting means 151 to 153 into fx, Fx, fy and Fy, respectively, based on the basic principle described in §4. , Fz and Fz. Further, each of the acceleration calculation means 171 to 173 calculates and outputs accelerations αx, αy, αz in each axial direction based on the relational expression of f = m · α using the mass m of the vibrator 130. It is. Since the acceleration acting on the vibrator 130 is detected as a force f irrespective of the vibration of the vibrator 130, each of the acceleration calculation means 171 to 173 performs the operation of each axis independently of the operation of each of the excitation means 141 to 143. The accelerations αx, αy, αz in the directions are output.

  On the other hand, each of the angular velocity calculating means 181 to 183 is a device which calculates and outputs the angular velocities ωx, ωy, ωz around each axis based on the principle shown in FIGS. However, the detection of the angular velocities ωx, ωy, ωz is closely related to the vibration of the vibrator 130 as shown in the principle diagrams of FIGS. In other words, each of the angular velocity calculation means 181 to 183 cannot calculate the angular velocity unless the operation state of each of the excitation means 141 to 143 is considered. This will be described for each individual case.

  First, in order to detect the angular velocity ωx about the X axis based on the principle shown in FIG. 3, in a state where the Z axis direction excitation means 143 is driven to give the vibrator 130 a Z axis direction vibration Uz, The Y-axis direction Coriolis force Fy separated by the axial signal separating means 162 is given to the angular velocity calculating means 182. The angular velocity calculating means 182 calculates an angular velocity ωx around the X axis based on a calculation formula of Fy = 2m · vz · ωx, and outputs this. At this time, the instantaneous velocity vz of the vibrator 130 in the Z-axis direction is estimated based on the operation mode of the Z-axis direction excitation means 143. For example, in the detection device having the specific structure described in §2, a predetermined AC voltage is supplied to the upper electrodes E1 to E4 to apply the vibration Uz, and the instantaneous speed of the vibrator 130 is It can be determined on the basis of the amplitude, frequency, and phase of the AC voltage supplied at the time (the relation between the supplied AC voltage and the instantaneous speed of the vibrator can be obtained by a theoretical operation formula, or It is also possible to prepare a table that measures the instantaneous velocity of the vibrator for one cycle of the AC voltage.) It should be noted that “FIG. 3: ωx (Uz)” is written in the output of the angular velocity calculating means 182 in FIG. 28 under the condition that the vibration Uz is given to the vibrator 130 based on the principle shown in FIG. The angular velocity ωx is output. ”

  Next, in order to detect the angular velocity ωy around the Y axis based on the principle shown in FIG. 4, in a state where the X axis direction excitation means 141 is driven to give the vibrator 130 the X axis direction vibration Ux, The Coriolis force Fz in the Z-axis direction separated by the Z-axis direction signal separating unit 163 is given to the angular velocity calculating unit 183. The angular velocity calculating means 183 calculates an angular velocity ωy around the Y axis based on an arithmetic expression of Fz = 2m · vx · ωy, and outputs this. At this time, the instantaneous speed vx of the vibrator 130 in the X-axis direction is estimated based on the operation mode of the X-axis direction excitation means 141. Note that "FIG. 4: ωy (Ux)" is described in the output of the angular velocity calculating means 183 in FIG. 28 under the condition that the vibration Ux is given to the vibrator 130 based on the principle shown in FIG. The angular velocity ωy is output. "

  Further, in order to detect the angular velocity ωz about the Z-axis based on the principle shown in FIG. 5, when the Y-axis direction excitation means 142 is driven to apply a vibration Uy to the vibrator 130 in the Y-axis direction, X The Coriolis force Fx in the X-axis direction separated by the axial signal separating means 161 is given to the angular velocity calculating means 181. The angular velocity calculating means 181 calculates an angular velocity ωz around the Z axis based on a calculation formula of Fx = 2m · vy · ωz, and outputs this. At this time, the instantaneous speed vy of the transducer 130 in the Y-axis direction is estimated based on the operation mode of the Y-axis direction excitation means 142. Note that the description of “FIG. 5: ωz (Uy)” in the output of the angular velocity calculation unit 181 in FIG. 28 is based on the condition that the vibration Uy is given to the vibrator 130 based on the principle shown in FIG. The angular velocity ωz is output. ”

  Thus, according to the detection device shown in FIG. 28, finally, the acceleration αx in the X-axis direction from the acceleration calculation means 171, the acceleration αy in the Y-axis direction from the acceleration calculation means 172, and the Z-axis acceleration from the acceleration calculation means 173. Are output from the angular velocity calculator 182, the angular velocity ωx around the X axis from the angular velocity calculator 183, the angular velocity ωy around the Y axis from the angular velocity calculator 183, and the angular velocity ωy around the Z axis from the angular velocity calculator 181. The angular velocities ωz are respectively output. In addition, the outputs “FIG. 31: ωy (Uz)”, “FIG. 32: ωz (Ux)”, and “FIG. 30: ωx (Uy)” are also obtained from the angular velocity calculating units 181 to 183 shown in FIG. This is described in §6.

  The detection device for detecting the accelerations αx, αy, αz in the respective axial directions and the angular velocities ωx, ωy, ωz around the respective axes by the detection device shown in FIG. 28 is described as “Detection according to the first embodiment. The operation is shown in the flowchart of FIG.

  First, in step S21, the combined force fy + Fy is extracted from the Y-axis direction force detection unit 152 in a state where the vibration Uz is applied to the oscillator 130 (that is, the state where the Z-axis direction excitation unit 143 is driven), and the Y-axis direction signal is obtained. The force fy and the Coriolis force Fy are separated by the separating means 162. Then, the acceleration calculating means 172 calculates the acceleration αy based on the force fy and outputs it, and the angular velocity calculating means 182 calculates the angular velocity ωx based on the Coriolis force Fy and outputs it. Thus, in step S21, the acceleration αy and the angular velocity ωx can be detected.

  Next, in step S22, in a state where the vibration Ux is given to the vibrator 130 (that is, a state where the X-axis direction excitation unit 141 is driven), the combined force fz + Fz is extracted from the Z-axis direction force detection unit 153, and the Z-axis direction is obtained. The force is separated into the force fz and the Coriolis force Fz by the signal separating means 163. Then, the acceleration calculating means 173 calculates the acceleration αz based on the force fz and outputs it, and the angular velocity calculating means 183 calculates the angular velocity ωy based on the Coriolis force Fz and outputs it. Thus, in step S21, the acceleration αz and the angular velocity ωy can be detected.

  Subsequently, in step S23, in a state where the vibration Uy is given to the vibrator 130 (that is, a state in which the Y-axis direction excitation unit 142 is driven), the combined force fx + Fx is extracted from the X-axis direction force detection unit 151, and the X-axis direction signal is obtained. The separating means 161 separates the force fx into the Coriolis force Fx. Then, the acceleration calculation means 171 calculates the acceleration αx based on the force fx and outputs it, and the angular velocity calculation means 181 calculates the angular velocity ωz based on the Coriolis force Fx and outputs it. Thus, in step S21, the acceleration αx and the angular velocity ωz can be detected.

  Finally, as long as the detection operation is continued after step S24, the processing from step S21 is repeatedly executed. In the “detection operation according to the first embodiment” shown in FIG. 29, one step is omitted from the “basic detection operation” shown in FIG. That is, in the “basic detection operation”, in order to perform the acceleration detection, in step S11, the detection was performed while the vibrator was kept in a stationary state. In the "detection operation", acceleration can be detected even when the vibrator is vibrated, so that it is not necessary to stop the vibrator. For this reason, the responsiveness of the detection device shown in FIG. 28 is improved as compared with the conventionally proposed detection device.

<<<< §6. Second Embodiment of Detection Device According to the Present Invention >>
By the way, in §5, the detection device having the basic configuration shown in FIG. 28 and its operation have been described. According to the operation, the angular velocity ωx about the X axis is output from the angular velocity calculating means 182 based on the principle of FIG. 3, and the angular velocity ωy about the Y axis is calculated based on the principle of FIG. And the angular velocity ωz about the Z axis is output from the angular velocity calculating means 181 based on the principle of FIG. However, in FIG. 28, the outputs of the angular velocity calculating means 181 to 183 are different from each other as “FIG. 30: ωy (Uz)”, “FIG. 31: ωz (Ux)”, and “FIG. There is a statement that output can also be obtained. This indicates that there are combinations of FIGS. 30 to 32 in addition to the combinations of FIGS. 3 to 5 as detection principles of each angular velocity. In other words, the detection of the angular velocity using the Coriolis force is as follows: “When the Coriolis force generated in the second coordinate axis direction is detected when the vibration is applied in the first coordinate axis direction, the angular velocity around the third coordinate axis is obtained. The first, second, and third coordinate axes in the basic principle are converted to the X, Y, and Z coordinate axes in the XYZ three-dimensional coordinate system. You can make it correspond.

  Although the method of detecting angular velocity ωx about the same X-axis is detected in FIG. 3, Coriolis force Fy generated in the Y-axis direction when vibration Zz in the Z-axis direction is applied is detected. At 30, the Coriolis force Fz generated in the Z-axis direction when the vibration Uy in the Y-axis direction is applied is detected. Further, in the method of detecting the same angular velocity ωy around the Y axis, in FIG. 4, the Coriolis force Fz generated in the Z axis direction when the vibration Ux in the X axis direction is applied is detected. In FIG. 31, the Coriolis force Fx generated in the X-axis direction when the vibration Uz in the Z-axis direction is applied is detected. Similarly, in the method of detecting the same angular velocity ωz about the Z-axis, in FIG. 5, the Coriolis force Fx generated in the X-axis direction when the vibration Uy in the Y-axis direction is applied is detected. On the other hand, in FIG. 32, the Coriolis force Fy generated in the Y-axis direction when the vibration Ux in the X-axis direction is applied is detected.

  Therefore, the detection device shown in FIG. 28 can be operated based on the principle shown in FIGS. This will be described for each individual case.

  First, in order to detect the angular velocity ωx about the X axis based on the principle shown in FIG. 30, when the Y axis direction excitation means 142 is driven to apply a vibration Uy to the vibrator 130 in the Y axis direction, Z The Coriolis force Fz in the Z-axis direction separated by the axial signal separating means 163 is given to the angular velocity calculating means 183. The angular velocity calculating means 183 calculates an angular velocity ωx around the X axis based on a calculation formula of Fz = 2m · vy · ωx, and outputs this. At this time, the instantaneous speed vy of the transducer 130 in the Y-axis direction is estimated based on the operation mode of the Y-axis direction excitation means 142. In the output of the angular velocity calculating means 183, "FIG. 30: ωx (Uy)" is written because "the angular velocity ωx is output under the condition that the vibration Uy is given to the vibrator 130 based on the principle shown in FIG. ".

  Next, in order to detect the angular velocity ωy around the Y axis based on the principle shown in FIG. 31, in a state where the Z axis direction excitation means 143 is driven to give the vibrator 130 the Z axis direction vibration Uz, The X-axis direction Coriolis force Fx separated by the X-axis direction signal separating unit 161 is given to the angular velocity calculating unit 181. The angular velocity calculating means 181 calculates an angular velocity ωy around the Y axis based on a calculation formula of Fx = 2m · vz · ωy, and outputs this. At this time, the instantaneous velocity vz of the vibrator 130 in the Z-axis direction is estimated based on the operation mode of the Z-axis direction excitation means 143. In the output of the angular velocity calculating means 181, “FIG. 31: ωy (Uz)” is written because “the angular velocity ωy is output under the condition that the vibration Uz is given to the vibrator 130 based on the principle shown in FIG. 31. ".

  Further, in order to detect the angular velocity ωz about the Z-axis based on the principle shown in FIG. 32, in a state where the X-axis direction excitation means 141 is driven to apply the vibration Ux in the X-axis direction to the vibrator 130, The Y-axis direction Coriolis force Fy separated by the axial signal separating means 162 is given to the angular velocity calculating means 182. The angular velocity calculating means 182 calculates an angular velocity ωz about the Z axis based on a calculation formula of Fy = 2m · vx · ωz, and outputs this. At this time, the instantaneous speed vx of the vibrator 130 in the X-axis direction is estimated based on the operation mode of the X-axis direction excitation means 141. In the output of the angular velocity calculating means 182, "FIG. 32: ωz (Ux)" is written because "the angular velocity ωz is output under the condition that the vibration Ux is given to the vibrator 130 based on the principle shown in FIG. ".

  Thus, both the detection method based on the three principles shown in FIGS. 3 to 5 and the detection method based on the three principles shown in FIGS. 30 to 32 are applied to the detection device shown in FIG. However, the inventor of the present application has noticed that the detection operation and the device configuration can be further simplified by properly selecting three principles out of the total of six principles. The second embodiment described here is a further simplification of the first embodiment described in §5 based on such a basic idea.

  Now, in the apparatus according to the first embodiment shown in FIG. 28, three detection principles of ωx shown in FIG. 3, detection of ωy shown in FIG. 31, and detection of ωz shown in FIG. Suppose you did. Then, the detecting device according to the first embodiment shown in FIG. 28 is simplified to the detecting device according to the second embodiment as shown in FIG. The detection device in FIG. 33 is obtained by removing the Y-axis direction excitation unit 142 and the angular velocity calculation unit 183 from the detection device in FIG. As long as the selected three detection principles shown in FIGS. 3, 31, and 32 are adopted, there is no need to apply the vibration Uy in the Y-axis direction, and it is not necessary to calculate the angular velocity using the Coriolis force Fz in the Z-axis direction. is there.

  The detection operation for detecting the accelerations αx, αy, αz in the respective axis directions and the angular velocities ωx, ωy, ωz about the respective axes by the detection device shown in FIG. 33 is described as “Detection according to the second embodiment. The operation is shown in the flowchart of FIG.

  First, in step S31, the following two types of detection are performed in a state where vibration Uz is applied to the vibrator 130 (that is, a state in which the Z-axis direction excitation unit 143 is driven). As a first detection, the combined force fy + Fy is extracted from the Y-axis direction force detection means 152 and separated into the force fy and the Coriolis force Fy by the Y-axis direction signal separation means 162. Then, the acceleration calculating means 172 calculates the acceleration αy based on the force fy and outputs it, and the angular velocity calculating means 182 calculates the angular velocity ωx based on the Coriolis force Fy and outputs it. This is a detection based on the principle of FIG. At the same time, the following second detection is performed. That is, the combined force fx + Fx is extracted from the X-axis direction force detection unit 151, and is separated into the force fx and the Coriolis force Fx by the X-axis direction signal separation unit 161. Then, the acceleration calculating means 171 calculates the acceleration αx based on the force fx and outputs it, and the angular velocity calculating means 181 calculates the angular velocity ωy based on the Coriolis force Fx and outputs it. This is detection based on the principle of FIG. Thus, in step S31, the accelerations αy, αy and the angular velocities ωx, ωy can be detected.

  Next, in step S32, the following two types of detection are performed in a state where the vibration Ux is applied to the vibrator 130 (that is, a state in which the X-axis direction excitation unit 141 is driven). As a first detection, the combined force fz + Fz is extracted from the Z-axis direction force detection unit 153, and separated into the force fz and the Coriolis force Fz by the Z-axis direction signal separation unit 163. Then, the acceleration calculating means 173 calculates the acceleration αz based on the force fz and outputs this. In the first detection, only the acceleration needs to be detected. (If the principle of FIG. 4 is used, the angular velocity ωy can be obtained based on the Coriolis force Fz, but the angular velocity ωy has already been obtained in step S31. It has been demanded). At the same time, the following second detection is performed. That is, the combined force fy + Fy is extracted from the Y-axis direction force detection means 152, and separated into the force fy and the Coriolis force Fy by the Y-axis direction signal separation means 162. Then, the angular velocity calculating means 182 calculates the angular velocity ωz based on the Coriolis force Fy and outputs this. This is detection based on the principle of FIG. Thus, in step S32, the acceleration αz and the angular velocity ωz can be detected.

  Finally, as long as the detection operation is continued after step S33, the processing from step S31 is repeatedly executed. The "detection operation according to the second embodiment" shown in FIG. 34 is one step less than the "detection operation according to the first embodiment" shown in FIG. That is, in the “detection operation according to the first embodiment”, the detection is performed in a state where the vibrator is vibrated in three directions of the X axis, the Y axis, and the Z axis. In the "detection operation according to the second embodiment", all the detections can be performed only in a state where the vibration is performed in the two directions of the X axis and the Z axis. Therefore, in the detection device shown in FIG. 33, the responsiveness is further improved.

<<<< §7. Third Embodiment of Detection Device According to the Present Invention >>
Until now, three-dimensional acceleration / angular velocity detection that detects six components of accelerations αx, αy, αz in each of the X, Y, and Z axes and angular velocities ωx, ωy, ωz around each axis. An example of the device has been described. However, depending on the application, the demand for a two-dimensional acceleration / angular velocity detecting device that only needs to obtain the accelerations αx and αy in two directions of the X axis and the Y axis and the angular velocities ωx and ωy around the two axes is sufficiently considered. Can be In the third embodiment in which the present invention is applied to such a two-dimensional detection device, the configuration is further simplified.

  FIG. 35 is a block diagram showing a basic configuration of the third embodiment. As compared with the second embodiment shown in FIG. 33, the X-axis direction excitation unit 141, the Z-axis direction force detection unit 153, and the acceleration calculation unit 173 are further omitted. Even with such a configuration, the required acceleration and angular velocity can be detected without any problem. That is, the acceleration αx is obtained by the acceleration calculator 171, and the acceleration αy is obtained by the acceleration calculator 172. Further, the angular velocity ωx is obtained by the angular velocity calculating means 182 in a state where the vibration Uz is applied by the Z-axis exciting means 143 (principle of FIG. 3), and the angular velocity ωy is given by the vibration Uz by the Z-axial exciting means 143. In this state, it is obtained by the angular velocity calculating means 181 (the principle of FIG. 31).

  The detection operation for detecting the accelerations αx, αy in the two axial directions and the angular velocities ωx, ωy around the two axes by the detection device shown in FIG. 35 is performed according to the “second embodiment” shown in FIG. Only step S31 in the "detection operation" is sufficient. In other words, the “detection operation according to the third embodiment” is an operation including only step S31 in FIG. This means that if the vibrator 130 is always vibrated only in the Z-axis direction, all detected values can be obtained. As described above, since it is not necessary to change the vibration mode of the vibrator, a very efficient detection operation becomes possible, and the responsiveness becomes extremely good.

<<<< §8. Specific detection device structure suitable for two-dimensional detection >>>>>
As described in §7 above, the two-dimensional detection device for the purpose of obtaining only the accelerations αx and αy in the two directions of the X-axis and the Y-axis and the angular velocities ωx and ωy around the two axes is not shown in FIG. As shown in the block diagram of FIG. 35, only the Z-axis direction excitation means 143 may be provided as the excitation means, and the X-axis direction force detection means 151 and the Y-axis direction force detection Only means 152 need be provided. Therefore, in such a two-dimensional detection device, the number of upper electrodes provided on the piezoelectric element can be reduced as compared with a three-dimensional detection device. For example, in the three-dimensional detection device shown in FIG. 10, on the piezoelectric element 10, four upper electrodes E1 to E4 functioning as excitation means, eight upper electrodes A1 to A8 functioning as force detection means, To realize excitation and force detection in all three axis directions. However, a two-dimensional detection device can be realized with a structure having fewer upper electrodes.

  FIG. 36 is a top view showing a specific example of the structure of a detection device suitable for two-dimensional detection, and FIG. 37 is a side sectional view of the detection device cut along the XZ plane. The correspondence between each upper electrode in this detection device and the block element shown in FIG. 35 is as follows. First, the upper electrode E10 functions as the Z-axis direction excitation means 143, and can apply a predetermined AC voltage between the upper electrode E10 and the lower electrode B to vibrate the center portion 11 in the Z-axis direction. it can. In addition, the upper electrodes A11 and A12 function as X-axis direction force detecting means 151, and can detect the displacement of the central portion 11 in the X-axis direction based on the charges generated here. Further, the upper electrodes A13 and A14 function as a Y-axis direction force detecting means 152, and can detect the displacement of the central portion 11 in the Y-axis direction based on the electric charge generated here. As a result, the two-dimensional detection device shown in FIG. 35 can be realized only by providing these five upper electrodes E10, A11 to A14 on the piezoelectric element 10.

  FIG. 38 is a top view showing another example of the structure of a specific detection device suitable for two-dimensional detection, and FIG. 39 is a side sectional view of the detection device cut along the XZ plane. The difference between the detection device shown in FIG. 38 and the detection device shown in FIG. 36 is that the positional relationship between the upper electrode for excitation and the upper electrode for force detection is reversed. The correspondence between each upper electrode in this detection device and the block element shown in FIG. 35 is as follows. First, the upper electrode E20 functions as the Z-axis direction excitation means 143, and by applying a predetermined AC voltage between the upper electrode E20 and the lower electrode B, the center portion 11 can be vibrated in the Z-axis direction. it can. In addition, the upper electrodes A21 and A22 function as X-axis direction force detecting means 151, and can detect the displacement of the central portion 11 in the X-axis direction based on the charges generated here. Further, the upper electrodes A23 and A24 function as a Y-axis direction force detecting means 152, and can detect the displacement of the central portion 11 in the Y-axis direction based on the electric charge generated here.

  As described above, in a detection device that requires only two-dimensional detection, the overall manufacturing cost can be reduced by configuring the upper electrodes with a minimum number.

<<<< §9. Capacitive detection device to which the present invention is applied >>>>>
As an example of the detection device to which the present invention is applied, in §2, the device using the piezoelectric element 10 has been described. As described above, the present invention can be applied to any detection device having a configuration as shown in the block diagram of FIG. 6, but here, for reference, An example of a capacitive detection device to which the present invention is applied will be briefly described. This detection device is disclosed in Patent Document 1 mentioned above.

  FIG. 40 is a side sectional view of this capacitance type detection device 200. The main components of this detection device are a flexure element 210, a vibrator 220, a pedestal 230, a base substrate 240, and a cover plate 250. FIG. 41 shows a top view of the flexure element 210. As shown in FIG. 41, the strain body 210 is a square metal plate, and an annular groove as shown by a broken line in FIG. 41 is formed on the lower surface thereof. As clearly shown in the side sectional view of FIG. 40, the thickness of the strain body 210 is reduced at the portion where the groove is formed, and this portion has a flexible structure. Here, the flexure element 210 is provided with the center portion 211 existing inside the annular groove portion, the thin flexible portion 212 existing above the annular groove portion, and the outer side of the annular groove portion. The existing peripheral portion 213 will be considered separately. The vibrator 220 is joined to the bottom surface of the central portion 211. The vibrator 220 is a disk-shaped metal lump having a certain mass, and acceleration and angular velocity are detected by a force based on the acceleration acting on the vibrator 220 or Coriolis force. On the other hand, a pedestal 230 is joined to the bottom surface of the peripheral portion 213 so as to surround the vibrator 220, and the bottom surface of the pedestal 230 is joined to the base substrate 240. As a result, the vibrator 220 is suspended in the space surrounded by the pedestal 230. Further, a lid plate 250 is joined to the upper surface of the strain body 210, and the lid plate 250 has a structure capable of securing a space inside as shown in the figure.

  An upper electrode E0 and lower electrodes F1 to F5 are arranged in a space formed between the upper surface of the strain body 210 and the lower surface of the cover plate 250. The lower electrodes F <b> 1 to F <b> 5 are electrodes having a shape as shown in FIG. 41, and are fixed to positions on the upper surface of the flexure element 210 as illustrated. On the other hand, the upper electrode E0 is a disk-shaped electrode that can function as a common electrode facing all of the five lower electrodes F1 to F5, and is fixed to the lower surface of the cover plate 250. As a result, five sets of capacitive elements are formed by the individual lower electrodes F1 to F5 and the common upper electrode E0.

  As described above, the vibrator 220 is suspended in the space surrounded by the pedestal 230, and the flexible portion 212 has flexibility. Can be moved with a certain degree of freedom. Therefore, if a predetermined AC voltage is applied between the electrodes, the vibrator 220 can be vibrated in a desired direction. For example, if charges of the same polarity are applied between the lower electrode F1 and the upper electrode E0, a repulsive force due to Coulomb force acts, and the distance between the two electrodes increases. At this time, if charges of different polarities are applied between the lower electrode F2 and the upper electrode E0 at the same time, an attractive force due to the Coulomb force acts, and the distance between the two electrodes is reduced. As a result, the vibrator 220 is displaced in the positive direction of the X axis. If the relationship between the repulsive force and the attractive force is reversed, the vibrator 220 will now be displaced in the negative direction of the X axis. Thus, if the positive and negative displacements along the X axis are performed alternately, the vibrator 220 vibrates along the X axis. Further, if the same is performed using the lower electrodes F3 and F4, the vibrator 220 can be vibrated along the Y axis. Furthermore, if the lower electrode F5 is used, vibration along the Z-axis direction is also possible. That is, if charges of the same polarity are applied to the lower electrode F5 and the upper electrode E0, the interval between the two electrodes is widened by the action of repulsion, and if charges of different polarities are applied, the gap between the electrodes is narrowed by the action of attraction. Then, the vibrator 220 vibrates along the Z-axis direction. As described above, this device is provided with the excitation means 141 to 143 in each axial direction shown in FIG.

  On the other hand, this device is a device also provided with force detecting means 151 to 153 in each axial direction shown in FIG. Now, consider a case where a force based on acceleration or a Coriolis force acts on the vibrator 220. For example, when a force is applied in the X-axis direction, the vibrator 220 causes a displacement in the X-axis, so that the distance between the lower electrode F1 and the upper electrode E0, the distance between the lower electrode F2 and the upper electrode E0, Will be changed. When a force is applied in the Y-axis direction, the vibrator 220 is displaced in the Y-axis direction. Therefore, the distance between the lower electrode F3 and the upper electrode E0 and the distance between the lower electrode F4 and the upper electrode E0. , Respectively. Further, when a force is applied in the Z-axis direction, the vibrator 220 is displaced in the Z-axis direction, so that the distance between the lower electrode F5 and the upper electrode E0 is changed. Such a change in the distance between the pair of opposed electrodes affects the capacitance value of the capacitor formed by the pair of electrodes. Therefore, if the change in the capacitance value of each capacitance element can be electrically detected, the displacement of the vibrator 220 can be detected, and as a result, each of the axial directions acting on the vibrator 220 can be detected. The force can be detected.

  As described above, the capacitive detection device 200 is a device including the excitation means 141 to 143 in each axial direction and the force detection means 151 to 153 in each axial direction shown in FIG. The present invention can be applied similarly to the above-described piezoelectric detection device. In the illustrated capacitive detection device 200, each of the lower electrodes F1 to F5 performs both functions of the excitation unit and the force detection unit. Thus, it is preferable that the part functioning as the excitation means and the part functioning as the force detection means have a physically separated structure.

<<<< §10. Selective use of each means >>>>>
As described above, the present invention relates to a device that can simultaneously detect a two-axis acceleration component and a one-axis angular velocity component, and a device that can simultaneously detect a one-axis acceleration component and a two-axis angular velocity component. Therefore, a number of examples have been described in which the three-axis components αx, αy, αz of acceleration and the three-axis components ωx, ωy, ωz of angular velocity can be detected. It is not necessary to provide all of the means constituting the embodiments described above. That is, as described in “Means for Solving the Problem”, a necessary means is selected from the respective means described in the previous embodiments according to the acceleration component and the angular velocity component that need to be detected. It is only necessary to adopt it.

FIG. 9 is a perspective view showing a basic principle of a conventionally proposed one-dimensional angular velocity detecting device using Coriolis force. FIG. 3 is a diagram illustrating angular velocities around respective axes in an XYZ three-dimensional coordinate system to be detected by the angular velocity detection device. FIG. 3 is a diagram illustrating a basic principle of detecting an angular velocity ωx around the X axis using the detection device according to the present invention. FIG. 3 is a diagram illustrating a basic principle of detecting an angular velocity ωy around a Y axis using the detection device according to the present invention. FIG. 3 is a diagram illustrating a basic principle of detecting an angular velocity ωz around the Z axis using the detection device according to the present invention. FIG. 3 is a block diagram showing components for detecting an angular velocity in the detection device according to the present invention. FIG. 3 is a block diagram showing components for detecting acceleration in the detection device according to the present invention. It is the perspective view which looked at the detecting device concerning the specific structural example of the present invention from diagonally above. FIG. 9 is a perspective view of the detection device shown in FIG. 8 as viewed obliquely from below. FIG. 9 is a top view of the detection device shown in FIG. 8. FIG. 9 is a side sectional view of the detection device shown in FIG. 8 cut along an XZ plane. FIG. 9 is a bottom view of the detection device shown in FIG. 8. FIG. 9 is a diagram illustrating polarization characteristics of a piezoelectric element 10 in the detection device illustrated in FIG. 8. FIG. 9 is a side sectional view showing a state where a displacement Dx in the X-axis direction is induced with respect to the center of gravity P of the detection device shown in FIG. 8. FIG. 9 is a side sectional view illustrating a state where a displacement Dz in the Z-axis direction is induced with respect to the center of gravity P of the detection device illustrated in FIG. 8. FIG. 9 is a side sectional view showing a state where a force fx in the X-axis direction acts on a center of gravity P of the detection device shown in FIG. 8. FIG. 9 is a side cross-sectional view illustrating a state where a force fz in the Z-axis direction acts on the center of gravity P of the detection device illustrated in FIG. 8. 9 is a table showing polarities of electric charges generated in each of the upper electrodes A1 to A8 when forces fx, fy, and fz in respective axial directions based on acceleration act on the detection device shown in FIG. FIG. 9 is a circuit diagram illustrating an example of a detection circuit used in the detection device illustrated in FIG. 8. 5 is a flowchart showing a procedure of a general detection operation of a detection device to which the present invention is applied. 5 is a graph showing specific conditions of vibration applied to a vibrator, applied angular velocity, generated Coriolis force, and applied acceleration in a detection device to which the present invention is applied. FIG. 22 is a graph showing a synthetic force actually detected under the conditions shown in FIG. 21. 23 is a graph showing a state in which inflection points P1 to P9 are obtained for the resultant force graph shown in FIG. 22. 24 is a graph showing a state where reference lines Q12 to Q89 are obtained based on inflection points P1 to P9 obtained in FIG. 25 is a graph showing a state where reference points m1 to m8 are plotted on reference lines Q12 to Q89 obtained in FIG. 26 is a graph illustrating a state in which a force f, which is a bias component of the resultant force, is extracted by connecting reference points m1 to m8 obtained in FIG. 25. 9 is a graph showing a state where an angular velocity is obtained as an envelope E of the Coriolis force Fy. FIG. 1 is a block diagram illustrating a basic configuration of a detection device according to a first example of the present invention. 29 is a flowchart showing a procedure of a detection operation of the detection device according to the first example shown in FIG. 28. FIG. 9 is a diagram illustrating another basic principle of detecting the angular velocity ωx around the X axis using the detection device according to the present invention. FIG. 9 is a diagram illustrating another basic principle of detecting the angular velocity ωy around the Y axis using the detection device according to the present invention. It is a figure explaining another basic principle which detects angular velocity ωz about the Z-axis using a detecting device concerning the present invention. FIG. 9 is a block diagram illustrating a basic configuration of a detection device according to a second example of the present invention. 34 is a flowchart showing a procedure of a detection operation of the detection device according to the second example shown in FIG. 33. FIG. 11 is a block diagram illustrating a basic configuration of a detection device according to a third example of the present invention. It is a top view which shows the structure of the specific detection apparatus suitable for two-dimensional detection. FIG. 37 is a side cross-sectional view of the detection device shown in FIG. 36 cut along an XZ plane. It is a top view which shows the structure of another specific detection apparatus suitable for two-dimensional detection. FIG. 39 is a side cross-sectional view of the detection device shown in FIG. 38 cut along an XZ plane. FIG. 1 is a side sectional view of a capacitive detection device 200 to which the present invention can be applied. FIG. 37 is a top view of a strain body 210 in the detection device shown in FIG. 36.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 ... Piezoelectric element 11 ... Center part 12 ... Flexible part 13 ... Peripheral part 15 ... Annular grooves 31-38 ... Q / V conversion circuits 41-43 ... Arithmetic unit 110 ... Vibrators 111 and 112 ... Piezoelectric element 120 ... Object 130 ... Vibrator 141 X-axis direction excitation means 142 Y-axis direction excitation means 143 Z-axis direction excitation means 151 X-axis direction force detection means 152 Y-direction force detection means 153 Z-axis direction force detection means 161 X-axis direction signal separation means 162 Y-axis direction signal separation means 163 Z-axis direction signal separation means 171 to 173 Acceleration calculation means 181 to 183 Angular velocity calculation means 200 Capacitive type detection device 210 Distortion element 211 Central part 212 Flexible part 213 Peripheral part 220 Transducer 230 Base 240 Base plate 250 Cover plates A, A1 to A8, A11 to A14, A21 to A24 Upper electrode B Lower electrode E: Envelopes E0, E1 to E4, E10, E20 Upper electrodes F1 to F5 Lower electrodes m1 to m8 Reference point O Origin P: Center of gravity P1 to P9 Inflection points Q1 to Q9 Partition lines Q12 to Q89 Reference lines Tx, Ty, Tz ... output terminals

Claims (5)

An apparatus for detecting an acceleration in a Y-axis direction in an XYZ three-dimensional coordinate system, and an angular velocity around the Y-axis and an angular velocity around the Z-axis,
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion having flexibility by connecting the vibrator and the fixed portion; and A structure configured such that the vibrator is displaced with respect to the fixed portion,
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency having the acceleration and the angular velocity to be detected;
First force detecting means for detecting a force in the Y-axis direction applied to the vibrator;
Second force detecting means for detecting a force in the Z-axis direction applied to the vibrator;
A first signal separating unit that separates a bias component and an amplitude component from a first detection signal obtained by the first force detecting unit;
A second signal separating unit that separates a bias component and an amplitude component from a second detection signal obtained by the second force detecting unit;
Acceleration calculation means for obtaining an acceleration in the Y-axis direction based on a bias component of the first detection signal;
A first angular velocity calculating means for oscillating the vibrator in the X-axis direction by driving the excitation means and obtaining an angular velocity about the Y-axis based on an amplitude component of the second detection signal obtained in this state; When,
A second angular velocity calculating means for driving the exciting means to vibrate the vibrator in the X-axis direction and obtaining an angular velocity about the Z-axis based on an amplitude component of the first detection signal obtained in this state; When,
An apparatus for detecting both an acceleration and an angular velocity, comprising: An apparatus for detecting acceleration in an X-axis direction in an XYZ three-dimensional coordinate system, angular velocity around a Y-axis, and angular velocity around a Z-axis,
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion having flexibility by connecting the vibrator and the fixed portion; and A structure configured such that the vibrator is displaced with respect to the fixed portion,
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency having the acceleration and the angular velocity to be detected;
First force detecting means for detecting a force applied to the vibrator in the X-axis direction;
Second force detecting means for detecting a force in the Y-axis direction applied to the vibrator;
Third force detecting means for detecting a force in the Z-axis direction applied to the vibrator;
A first signal separating unit that separates a bias component and an amplitude component from a first detection signal obtained by the first force detecting unit;
A second signal separating unit that separates a bias component and an amplitude component from a second detection signal obtained by the second force detecting unit;
A third signal separating unit that separates a bias component and an amplitude component from a third detection signal obtained by the third force detecting unit;
Acceleration calculating means for obtaining an acceleration in the X-axis direction based on a bias component of the first detection signal;
A first angular velocity calculating means for driving the exciting means to vibrate the vibrator in the X-axis direction, and for obtaining an angular velocity about the Y-axis based on an amplitude component of the third detection signal obtained in this state; When,
A second angular velocity calculating means for driving the excitation means to cause the vibrator to vibrate in the X-axis direction and for obtaining an angular velocity about the Z-axis based on an amplitude component of the second detection signal obtained in this state; When,
An apparatus for detecting both an acceleration and an angular velocity, comprising: An apparatus for detecting an acceleration in a Y-axis direction and an acceleration in a Z-axis direction in an XYZ three-dimensional coordinate system, and an angular velocity around the Z-axis,
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion having flexibility by connecting the vibrator and the fixed portion; and A structure configured such that the vibrator is displaced with respect to the fixed portion,
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency having the acceleration and the angular velocity to be detected;
First force detecting means for detecting a force in the Y-axis direction applied to the vibrator;
Second force detecting means for detecting a force in the Z-axis direction applied to the vibrator;
A first signal separating unit that separates a bias component and an amplitude component from a first detection signal obtained by the first force detecting unit;
A second signal separating unit that separates a bias component and an amplitude component from a second detection signal obtained by the second force detecting unit;
First acceleration calculation means for obtaining an acceleration in the Y-axis direction based on a bias component of the first detection signal;
Second acceleration calculation means for obtaining acceleration in the Z-axis direction based on a bias component of the second detection signal;
Driving the exciting means to oscillate the vibrator in the X-axis direction, and calculating angular velocity about the Z-axis based on an amplitude component of the first detection signal obtained in this state;
An apparatus for detecting both an acceleration and an angular velocity, comprising: An apparatus for detecting an acceleration in a Y-axis direction and an acceleration in a Z-axis direction in an XYZ three-dimensional coordinate system, and an angular velocity around the Z-axis,
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion having flexibility by connecting the vibrator and the fixed portion; and A structure configured such that the vibrator is displaced with respect to the fixed portion,
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency having the acceleration and the angular velocity to be detected;
First force detecting means for detecting a force in the Y-axis direction applied to the vibrator;
Second force detecting means for detecting a force in the Z-axis direction applied to the vibrator;
Signal separating means for separating a bias component and an amplitude component from a first detection signal obtained by the first force detecting means;
First acceleration calculation means for obtaining an acceleration in the Y-axis direction based on a bias component of the first detection signal;
Second acceleration calculating means for obtaining acceleration in the Z-axis direction based on a second detection signal obtained by the second force detecting means;
Driving the exciting means to oscillate the vibrator in the X-axis direction, and calculating angular velocity about the Z-axis based on an amplitude component of the first detection signal obtained in this state;
An apparatus for detecting both an acceleration and an angular velocity, comprising: An apparatus for detecting an acceleration in an X-axis direction and an acceleration in a Y-axis direction in an XYZ three-dimensional coordinate system, and an angular velocity around the Z-axis,
A vibrator having a mass, a fixed portion fixed to the device housing, and a flexible portion having flexibility by connecting the vibrator and the fixed portion; and A structure configured such that the vibrator is displaced with respect to the fixed portion,
Exciting means for causing the vibrator to vibrate in the X-axis direction at a sufficiently high frequency that can be identified with respect to the frequency having the acceleration and the angular velocity to be detected;
First force detecting means for detecting a force applied to the vibrator in the X-axis direction;
Second force detecting means for detecting a force in the Y-axis direction applied to the vibrator;
A first signal separating unit that separates a bias component and an amplitude component from a first detection signal obtained by the first force detecting unit;
A second signal separating unit that separates a bias component and an amplitude component from a second detection signal obtained by the second force detecting unit;
First acceleration calculation means for obtaining an acceleration in the X-axis direction based on a bias component of the first detection signal;
Second acceleration calculating means for obtaining an acceleration in the Y-axis direction based on a bias component of the second detection signal;
Driving the exciting means to oscillate the vibrator in the X-axis direction, and calculating angular velocity about the Z-axis based on an amplitude component of the second detection signal obtained in this state;
An apparatus for detecting both an acceleration and an angular velocity, comprising: